The present invention relates generally to a braking systems, and more particularly to a safety indicator for parking brake systems which indicates to the driver of a commercial truck that the parking brake is not engaged.
A severe safety hazard has arisen with regard to the application of parking brakes on commercial trucks which make frequent stops or pickup, such as delivery trucks and waste hauling trucks or garbage trucks. These trucks generally have pneumatically operated parking brake systems which the drivers are required to engage each time they leave the truck cab to make a pickup, a rest stop, or for other purposes. As a result severe accidents have occurred wherein the unattended vehicle rolls away creating severe damage and even resulting sometimes in severe injury or death to pedestrians.
Various systems have been developed over the years in an attempt to avoid this problem. For example, one system, such as shown in U.S. Pat. No. 6,758,298, automatically applies the parking brake when the driver's not seated. However, this is problematic as a driver might momentarily rise, or be caused to rise from the driver's seat thereby inappropriately activating the system and of course such a system would not work in the truck cabs wherein no seat is provided for the driver and the driver is always in a standing position. For example, this is sometimes the situation with short delivery route trucks. Another system prevents the vehicle door from opening until the parking brake is set. For example, see U.S. Pat. No. 4,546,845. This reference applies to train doors, but nevertheless, even if incorporated in a truck this could be disastrous in an accident situation wherein the driver would be prevented from escaping from the vehicle.
U.S. Pat. No. 6,234,525 discloses a driver restraint device in the form of a pivoting bar that acts as a safety harness belt. The safety belt restraining device is configured to release the parking brake as a function of the position of the bar/seatbelt combination. Such a device simply is not practical for trucks wherein the driver must make frequent exits from the cab, such as is the situation for waste pickup trucks.
Accordingly, it is a principal object of the present invention to provide a system which definitely reminds the operator of the truck to set the parking brake for exiting the vehicle, yet does not hinder an escape from the cab in the event of an emergency, and further provides a system which is devoid of the aforementioned disadvantages.